Re: [Xen-users] Re: creating a xen failover with lookback images

[Heiko <rupertt@xxxxxxxxx>]

On Mon, Jul 28, 2008 at 1:18 PM, Heiko <rupertt@xxxxxxxxx> wrote:
> On Thu, Jul 24, 2008 at 7:19 PM, Daniel Asplund <danielsaori@xxxxxxxxx> wrote:
>>>> Hello,
>>>> i want to setup a VM which has another VM as failover.
>>>> We use images where we store the VM in.
>>>> Most people use drbd and heartbeat for this, is this the best solution
>>>> fors this?
>>>>
>>>> When I use XEN images, how do I have to define the image in drbd?
>>>>
>>>>  on ares.bluethings.net {
>>>>    device     /dev/drbd0;
>>>>    disk       /dev/sda5;
>>>>    address    172.16.6.2:7788;
>>>>    flexible-meta-disk  internal;
>>>>  }
>>>>
>>> Am I right that the guy in this
>>> http://marksitblog.blogspot.com/2007/07/mysql-5-high-availability-with-drbd-8.html
>>> guide is using drbd inside the VM to mirror the /dev/sda1 inside the VM?
>>>
> Hi Daniel,
> i reinstalled both servers and now have LVM.
> Since I dont use the Xen-tools and use CentOS, i would like to install
> the VM with virt-install,
> I started the installation with:
>
> virt-install \
> --name=ticketsystem \
> --ram=2000 \
> --file=/dev/vg01/lv_myVM \

--file=/dev/vg01/lv_myVM \  should be --file=/dev/drdb0 i guess

> --vcpus=2 \
> --os-variant=centos5 \
> --nographics \
> --location ftp://wftp.tu-chemnitz.de/pub/linux/centos/5.2/os/x86_64/ \
>
> it ran thorugh, now I did shut it down and changed the VM config:
>
> disk = [ "drdb:ticketsystem,xvda1,w" , 
> "file:/VM/ticketsystem_swap.img,xvda2,w"]
>
should be  disk = [ "drbd:ticketsystem,xvda1,w" ,
"file:/VM/ticketsystem_swap.img,xvda2,w"]



> [root@pc] xm create ticketsystem -c
> Using config file "/etc/xen/ticketsystem".
> No handlers could be found for logger "xend"
> Error: Disk isn't accessible
>
> It looks like xend doesnt like the drbd thing?
>
> how can i get this working?
>
> thx
>
>>> thx
>>>
>>
>> Yeah, he is running DRBD inside the VM to allow for failover with
>> heartbeat of the VMs.
>>
>> I believe using LVM, DRBD and heartbeat is the best solution for this,
>> it will give you a very flexible solution. I run this myself. Not
>> inside the VMs but on the Dom0 nodes. But the principle is the same
>> when configuring it. Cool solution would be to run a cluster both on
>> the Dom0s and inside the DomUs, maybe something to try. :)
>>
>
>
>> Please have a look at my XEN cluster guide at:
>> http://www.asplund.nu/xencluster/xen-cluster-howto.html
>> It is not fully complete but maybe you can get some ideas about the DRBD 
>> setup.
>>
>> Cheers, Daniel
>>
>> _______________________________________________
>> Xen-users mailing list
>> Xen-users@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-users
>>
>

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